Barrel extension and coupling device for attachment to gun barrels



March 6, 1951 a. B. DAVIS, JR 2,543,766 BARREL EXTENSION AND COUPLING DEVICE FOR ATTACHMENT TO GUNIBARRELS Filed Jan. 16, 1946 2 Sheets-Sheet 1 Gec qe BIJavi-a J1:

mMu/MMM Moms March 6, 1951 e. B. DAVIS, JR 2,543,766

BARREL EXTENSION AND COUPLING DEVICE FOR ATTACHMENT TO GUN BARRELS Filed Jan. 16, 1946 2 Sheets-Sheet 2 !1 ll 79 r 77 1" I I5 r4 5 I m i L Fig 4:-

Genr ge ELDEViS Jr.

Patented Mar. 6, 1951 OFFICE BARREL EXTENSION AND COUPLING DEVICE FOR ATTACHMENT TO GUN BARRELS George B. Davis, Jr., Green Acres, Md., assignor to the United States of America as represented by the Secretary of War Application January 16, 1946, Serial No. 641,554

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) 1 Claim.

The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

The present invention relates generally to a gun of the type known to the art as a mortar.

More particularly it relates to a coupling device for attaching a barrel extension to the main barrel of a mortar.

In the past attempts have been made to provide guns of the mortar type with an auxiliary barrel adapted to be attached to the normal barrel thereof in order to increase the firing range as well as for other reasons. Considerable difficulty has been experienced, however, in obtainin a coupling device for securing the main and auxiliary barrels together which would be capable of resisting the pulling force tending to separate the barrels during the passage of a projectile therethrough and which at the same time would effect satisfactory sealing to prevent the escape of the gases of propulsion at the joint between the barrels.

It is accordingly, an important object of the present invention to provide a gun of the mortar type having a novel coupling member for securing an auxiliary barrel thereto.

Another object of the invention resides in the provision of a novel coupling device wherein means is provided for securing the coupling device to a mortar barrel and additional means is provided for sealing said barrels against the escape of propulsion gases therebetween.

A still further object of the present invention resides in the provision of a novel sealing device of general utility for preventing the escape of pressure fluid between two concentric cylinders wherein a resilient sealing ring is secured to one of said cylinders having a portion overlying but spaced from the bottom of a groove formed therein and in engagement with the other cylinder.

The above as well as other and further objects and advantages of the invention together with a more exact understanding thereof will become more readily apparent to one skilled in the art from a consideration of the following detailed specification taken in conjunction with the accompanying drawings illustrating a preferred embodiment thereof wherein:

Figure 1 is a front elevational view of a mortar tube having a barrel extension and coupling member secured thereto;

Figure 2 is a plan view of the coupling member of Figure 1;

Figure 3 is a longitudinal, cross sectional view taken along the line 3-3 of Figure 2;

Figure 4 is a transverse cross sectional view taken along the line 4-4 of Figure 1;

Figure 5 is a transverse cross sectional view taken along the line 55 of Figure 1; and

Figure 6 is a fragmentary longitudinal cross sectional view of the sealing device per se illustrated in Figure 3.

Referring now particularly to Figure 1 of the drawings there is illustrated a mortar comprising a conventional mortar tube I0 having a base cap I I attached thereto and including a spherical member [2 adapted to engage in a base plate socket in a manner well known to the art. A barrel extension I3 is secured to the main barrel Ill by means of a generally cylindrical tubular coupling [4. Both the main barrel Ill and auxiliary barrel l3 are distorted in Figure 1 from their true length having been broken as indicated for accommodation on a single sheet. The coupling member I4 is provided intermediate its ends with a transverse saw-cut 15 extending approximately half way through the coupling. As illustrated most clearly in Figures 2 and 4 a similar cut away portion I6 is provided longitudinally of the collar I4 between one end thereof and the transverse cut l5 to provide a pair of slightly flexible clamping elements I! and [8. The clamping element I! is provided with an upstanding lug 19 having a threaded aperture 20 therein and suitable reenforcing webs 2| at opposite sides thereof. The member IB is similarly provided with an upstanding lug 22 having reenforcing webs 23 attached thereto although the aperture in lug 22 is not threaded. A clamping bolt 24 having an operating handle 25 and a threaded portion 26 thereon is adapted to be inserted through the aperture in lug 22 the threaded portion 26 engaging with the internal threads formed in the aperture 2|]. It will be noted that the bolt 24 is provided with a smooth portion 21 journaled within the aperture in member 22 in such manner that rotation of the bolt 24 by means of the operating handle 25 will result through the engagement of the threaded portions 2|] and 26 in pulling the lugs l9 and 22 towards each other which in turn pulls the members l1 and I8 together to securely clamp the coupling [4 to the outer surface of the main mortar barrel H). A collar 28 is mounted on the threaded portion 26 of the bolt 24 and is normally secured in engagement therewith by means of a set screw 29 so that should the coupling [4 tend to freeze to the barrel I0 reverse rotation of the 3 bolt 24 will result in forceably sliding the lugs and I9 and 22 apart to release the coupling ll from the barrel I0.

Referring now particularly to Figures 3, and 6 the specific sealing or obturating device constituting an important part of the present invention is illustrated in detail. As will be noted particularly in Figure 6 the top portion of the main mortar barrel [I] is provided with an outwardly curved lip 38 for facilitating the insertion of a projectile therein when the mortar is used without the barrel extension attached thereto. The coupling. Mi has been illustrated as comprising a separate sleeve secured in any suitable manner as, for example, by furnace brazing at the area 30- to the barrel extension l3. An internal, elongated, annular groove 3| is provided in the collar l4 and a generally cylindrical, resilient obturating or sealing:

ring 32, which may be made preferably of bronze, brass, or steel, is securely attached to a notch formed in the collar i4 adjacent to the groove! in any suitable manner such as, for example, by silver soldering or furnace brazing at the area designated generally by the reference numeral 3-3. 'Anaperture 35 is provided between the end of the sealing ring 32- and the end of the groove 3! to provide for the admission of gases under pressure which may escape through the passage 39 adjacent to the abutting joint and passage 35 between the main barrel in and the barrel extension iB. It will be appreciated that the size of. the'passages as and 35 have been exaggerated in Figure 6- inorder tomore ciearly illustrate the functioning of the seal. In any event it is assumed that a certain amount of gas under pressure will always leak: through the passages 34 and 35 under the high pressures existing in the tube during firing of a projectile therefrom. As the gas under pressure passes through the passages 3t and 35 and through the aperture 34 into the groove 3-5 it tends to exert pressure upon the outer face of the sealing member 32 forcing the forward lip 35 of the latter into sealing engagement with the outer wall of the barrel l0. By this arrangement the sealing effect of the member 32 is increased in proportion to the in crease of pressure caused by leakage of gases into the groove 3| so that further leakage past the sealing lip 36 is substantially prevented.

Obviously, numerous other modifications, deviations andalterations from the specific structures disclosed herein for purposes of illustration will occur to one skilled in the art without departing from the spirit or scope of the invention as set forth in the appended claim.

I claim:

An extension for attachment to the end of a gun barrel comprising a barrel-engaging collar attached to one end of said extension and extending beyond said extension, said collar having an internal diameter substantially equal to the external diameter of a gun barrel with which the, extension may be used, said collar having a partial circumferential split and an axial split extending from the free end of the collar to thecircumferential split to provide two curved clamping arms, radially upstanding lugs attached near the:- ends of said clamping arms, and means for forcibly drawing said clamping arms toward each other, a circumferential groove on the internal surface of said collar between said circumferential' split and the region of attachment of said collar to said extension, and a resilient metal obturating ring attached internally at the end nearest to said split collar coaxially therewith and having its other end lying within said groove.

GEORGE E. DAVIS, JR.

REFERENCES CITED The following references are of record in the 

